Social media on the internet have the recent years contributed in changing people's way of communication. Continuing increasing capacity and presence of wireless networks have in addition contributed to that it is now possible to communicate via social media almost from anywhere someone is located. This has brought about that people in continuing increasingly degree uses social networks in order to pass on and exchange information of what one does or takes part in. This is communicated either in the form of text, image, video, or a combination of these. This way of communication is spreading in society and has become enormously popular worldwide.
A particular use of this technology is to find oneself or others in images shared with friends in social networks. To make oneself visible in this way illustrates a need or a wish to show that one is taking part in something, either alone or together with others. Today one has to identify oneself or others in an image manually or by image recognition. For this a tag is used. In addition to the meaning electronic label, the word tag is also used in social networks on the internet for the act of finding or publishing information in lists/images. On Facebook it is most often used about the act of identifying or referring to persons in an image.
US2007/0288499 describes a solution where a mobile phone with camera or a digital camera/video camera is provided with an RFID reader. An RFID transponder tag is arranged in a point of interest, e.g. an historical monument. The tag has stored thereon data about the historic monument which is transmitted to the RDID reader on the camera. A user of the camera may then take an image of and also receive information about the monument. The multimedia file will then be tagged, and the improved multimedia file may then be able to contain information which was read by the RFID reader about the monument together with the image, which later may be experienced locally by the user. The tag may be supplemented with generated time/date or a GPS position from the mobile.
US 2010/0103173 A1 concerns a method for tracking an object in an image, where the position of the object in the 3D space is determined. An RF tag (e.g. an RFID tag) is attached to the object. The system uses trilateration and an external positioning apparatus must be arranged close to the object for receiving the signals from the RF tag. Trilateration requires that three (or more) transmitter/receiver units are placed surrounding the ID tags that shall be positioned. By measuring the time it takes for a signal to travel from an ID tag to three different points in space, it is possible by triangulation to determine the point in space from which the signal was transmitted and thereby enable determination of the position of the ID tags.
Hislop, D. Lekime, M. Drouguet, and C. Craeye, “A prototype 2D direction finding system with passive RFID tags,” in Proc. European Conference on Antennas and Propagation, April 2010, Barcelona, Spain, concerns a system for refinding passive RFID tags along a corridor inside a warehouse. A digital camera is arranged in the middle of an antenna arrangement. Camera with antennas is placed in a fixed position in a warehouse with known dimensions. The location of the passive RFID tag will be registered and its position may be marked on an image. The system is not designed to solve the need of which the present invention is focused, as the system is based on dedicated readers that are not owned by common people and that do not have a practical size. The system is also developed for refinding items where one knows what one is looking for. The system provides a confirmation that the item is present and where it is.
An alternative wireless position technology is GPS. It may be used to provide information about where an image is taken (photographic position), but does not alone provide any information about what or who is present in the image.
US2005/0104956 describes a system for personal identification of imaged products. Information from a tagged item is combined with an image of the item itself. The tag is in the form of a RF tag. In order to establish an estimate of the direction to a tagged object relative to the imaging device, a moving image is required. The moving image enables each individual RF tag to be tracked by an imaging device using a high directivity antenna beam at its maximum peak. The information obtained from the tagged objects serve as information in a dedicated database, where it is used to find a match between similar imaged products. However, when the antenna is of limited size, as will be the case for antennas on imaging devices as mobile phones it may not be possible to produce a high directivity radiation pattern in order to locate the RF tag. Also multipath propagation creates false signals a problem which is unsolved in the prior art.